1. Field of the Invention
The present invention relates to torque screwdrivers. More particularly, the present invention is related to a torque screwdriver, including means to lock the torque screwdriver in various selected measurement units. It will lock and coordinate indexing numerals on an adjustment cap with other indexing numerals included on the shaft, allowing the operator to maintain or to select a different torque value.
2. Background Art
In the past, manufacturers of torque screwdrivers have only had screws, levels and lock rings to lock in a selected torque setting.
A search of the background art directed to the subject matter of the present invention conducted in the U.S. Patent and Trademark Office disclosed the following U.S. Pat. Nos.:
______________________________________ 2,440,683 Hattan 3,896,540 Ellis 2,491,325 McVey 4,063,474 Klopping 2,729,134 Stanton 4,901,610 Larson 2,933,959 McMahon 5,501,124 Ashby 3,001,430 Cranford 5,662,012 Grabovac ______________________________________
A thorough review of the above-identified patents has concluded that none are believed to claim teach or disclose the particular novel combination of elements and functions set forth in the present invention. While U.S. Pat. Nos. 2,729,134, 3,001,430, 4,901,610, 5,501,124, and 5,662,012 all include locking means, it will be seen that none of these are structurally or functionally similar to the improved lock of the present invention.
Accordingly, it is the object of the present invention to selectively lock or release each torque setting selection into positive incremental and indexable positions, making possible maintenance and guaranteed accuracy of the selection of torque value settings.
Another object of the present invention is to be sure that each one of the torque value settings can be changed to a different accurate torque value.